1. Field of the Invention
The present invention relates to internal combustion engines and, more specifically, to a cylinder liner for a coolant groove-type internal combustion engine.
2. Description of the Prior Art
Internal combustion engines, such as diesel and gasoline engines, are heat engines in which the burning of a fuel occurs in a confined space to create gases of high temperature and pressure. The gasses are permitted to expand in the engine to do work. Typically, an internal combustion engine includes a cylinder into which fits a piston. The fuel is burned in the space formed by the cylinder and the piston, driving the piston outwardly when the burning gasses expand. The piston is usually coupled to a connecting rod that transfers the reciprocating lateral motion of the piston to a crank shaft. The crankshaft translates the lateral motion to rotary motion, which is ultimately applied to perform useful work.
Modern truck engines tend to have more horsepower than earlier designs. This increased horsepower results in higher a heat output and a corresponding need for greater cooling capacity. To facilitate cooling of the pistons and cylinders, one prior art system, a coolant groove-type internal combustion engine as shown in FIGS. 1A-1C, includes a cylinder block frame 14 having a longitudinal 16 surface and a lateral member 18 transverse to the longitudinal surface 16. The lateral member 18 defines a coolant passage 20 therethrough and also defines at least one cylinder opening 22. A groove coolant port 28 extends from the coolant passage 20 to the cylinder opening 22. A coolant return 40 is spaced apart from the groove coolant port 28.
A cylinder liner 10 fits into the cylinder opening 22 and defines an elongated cylinder bore 32, into which fits a piston 24. The cylinder liner 10 has an outer surface 30, which forms a coolant jacket 38 (also referred to as a “water jacket”) between the outer surface 30 of the cylinder liner 10 and the longitudinal surface 16. The outer surface 30 of the cylinder liner 10 includes a coolant groove 34 that is aligned with the groove coolant port 28.
Coolant is allowed to flow around the coolant groove 34 between the groove coolant port 28 and the coolant return 40, thereby facilitating cooling of the piston liner 10. However, in current designs, the groove coolant port 28 and the coolant return 40 both feed into the coolant jacket 38 without a pressure differential between the groove coolant port 28 and the coolant return 40. Thus, the coolant flow rate through the coolant groove 34 cannot be assured. When the coolant flow rate drops below a critical point, the coolant can boil and form steam in the coolant groove 34. Since steam acts as an insulator, steam formation can result insufficient cooling, especially in the upper portions of the cylinder liner. It can also result in excessive pressure in the cooling system. Both of these phenomena can lead to degraded engine performance and reduced lifetime.
Therefore, there is a need for cylinder liner that may be fitted into a coolant groove-type internal combustion engine that prevents steam formation in the upper portions of the cylinder liner.